to think a 15 week old baby shouldn't be in a forward facing carseat?

[SpaghettiTwirlerAndProud]

We saw BIL and SIL over the weekend with their 15 week old DS, and 2 DDs, the DS is in a forward facing seat already, as he has outgrown his old one yes he's big (bigger than our 5mo DD), but not as big as a 1yr old which is what age his old one went upto!

Isn't there a law or something about this kind of thing?

Yanbu I would tell them how ignorant and dangerous they were being. My friend dis the same thing at 6 months as she had just passed her test and was apparently "thinking ahead" so she wouldn't have to replace it. I told her to get a grip and stop endangering her child for the sake of a few quid saved in the long run. Whether or not they will listen its still worth a shot if only for your own peace of mind

Having done some reading, forward facing car seats are not a lot better at protecting children than seat belts only. Rear-facing car seats are great at protecting babies. DD is one and in rear facing. She is 90 and 100 percent for weight and height. She's going to be in it until her knees are at her chin

My SiL started banging on about doing the same with her 4month old 'cos he's such a big boy'. He's not he's just larger side of average). I strongly advised against and told her to get a rear facing seat. I understand it's very difficult to say anything. SIL has done lots of things that are directly contrary what I regard as basic safety rules - for example putting him to sleep on the sofa and leaving the room. She's meant to be an intelligent woman, and I understand people have their own level of risk they are willing to tolerate, but some people are just idiots. I know she and her dh think I am an interfering old bag but I feel that if it's in the interest of safety and I say something once and if they choose to ignore it then that's all I can do.